CI: Drop support for macOS 14

GitHub retired macOS 14 runners on November 2, 2026, so wheel jobs fail
before any build steps run.  This patch bumps the supported macOS
runners to macOS 15, which still receives security updates.

Signed-off-by: Patrick M. Niedzielski <pniedzielski@bloomberg.net>

Author: pniedzielski

.github/workflows/build_wheels.yml

@@ -113,7 +113,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [macos-14]
+        os: [macos-15]
         cibw_python:
           ["cp39", "cp310", "cp311", "cp312", "cp313", "cp314", "cp315"]
         cibw_arch: ["arm64"]
@@ -137,7 +137,7 @@ jobs:
       - name: Sets env vars for compilation
         if: matrix.cibw_arch == 'arm64'
         run: |
-          echo "CFLAGS=-target arm64-apple-macos14" >> $GITHUB_ENV
+          echo "CFLAGS=-target arm64-apple-macos15" >> $GITHUB_ENV
       - name: Build wheels
         uses: pypa/cibuildwheel@f9b966cfadf4109556cadc5bb39ddb72d0ce664e # v4.3.5
         env:
@@ -146,7 +146,7 @@ jobs:
           CIBW_BUILD_VERBOSITY: 1
           CIBW_TEST_COMMAND: python3 -m pytest {project}/tests/unit
           CIBW_TEST_REQUIRES: pytest mock pkgconfig
-          MACOSX_DEPLOYMENT_TARGET: "14.0"
+          MACOSX_DEPLOYMENT_TARGET: "15.0"
           SYSTEM_VERSION_COMPAT: 0
 
       - uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2